<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <div id="app">
    <!--

    -->
    <h2>当前计数:{{counter}} </h2>
    <!-- <button v-on:click='counter++'>+</button>
    <button v-on:click='counter--'>-</button> -->
    <button v-on:click="add">+</button>
    <button @click="sub">-</button>
  </div>

  <script src="../js/vue.js"></script>
  <script>
    const app = new Vue({
      el:'#app',
      data:{
        counter:0
      },
      methods:{
        add:function(){
          this.counter++
        },
        sub:function(){
          this.counter--
        }
      },
      beforeCreate:function(){
        console.log("beforC")
      },
      created:function(){
        console.log('created')
      },
      mounted:function(){
        console.log('mounted')
      }
      
    })

    //1.拿button元素
    //2.添加监听事件
  </script>
</body>
</html>